6.0 Deployment Work on Wednesday, August 23, 2000

Jim Irish attached the load cell to a Synergetics data system and logged the results on a notebook computer. The line tension was measured at 5 second (for the first part of the tow) and 2 second (for the last part of the tow) intervals during the tow to an accuracy of ±5 lbs. Also, a GPS receiver was recorded at 1-second intervals on a second notebook computer to determine the ship's position and to measure its speed over the bottom. A typical tow speed of 1.5 knots generated an average of 3,300 lbs. of tension. The tension varied with the waves about this mean with peak loads of greater than 5,000 lbs. (variations of 1,000 to 5,000 lbs. were typical). The tension was kept below 5,000 lbs. to avoid damaging the Gulf Challenger's A-frame. The cage was at towed at varying velocities to investigate the load - speed relationship.

David Fredriksson measured the water velocities relative to the ship during the tow by three means and collected data at approximately one half hour intervals with the help of whoever was handy. A Marsh-McBirnery electromagnetic current meter was used to collect water velocities over the side of the towing vessel at a depth of about 0.3 meters. A second measurement was made with the Gulf Challenger’s onboard ADCP at a depth of 5.12 meters. A third measurement was made with an internally recording S4 electromagnetic current meter placed inside the fish cage at a depth of 3 meters. The intent of the internal cage velocity measurement was to investigate the net blockage.

Back at the Port Authority Pier, the Nobska started loading the remaining mooring components for the Northwest and Northeast anchor deployments at 7 AM with the aid of the Badger Rand crane. The mooring gear again consisted of two anchor line moorings and their crown or pickup moorings as shown in Figures 2, 3, and 4 and the remaining grid lines and all the bridle lines. Loading was done as described for Tuesday, 22 August. While heading out to sea, the fully loaded Nobska (see Picture 35) passed the Gulf Challenger with the fish cage in tow (Picture 34) on her slow journey to the OOA site.

Once on station the Nobska deployed the Northwest and Northeast anchor line moorings at their designated positions (100 feet toward the center from their final desired position) with help of the crown line assemblies. The grid line was attached between the two northern grid corner rings so that the east-west channel between the moorings was free to tow the fish cage into position on the following day. Michael Chambers was on board the Nobska to aid with the anchor-line mooring deployment. Walter Paul had brought the four-load cells and grid corner ring that was to go into the Northeast corner.

During the afternoon, the prevailing southeast wind increased to 15 knots and started to build a short choppy sea. After completion of the mooring deployment around 2:30 PM, the Nobska checked the southern cage anchors/crown buoys, but did not have any material on board to undertake any of the planned servicing there. Therefore, the Nobska took over the cage tow from the Gulf Challenger who was slowed to about _ knot speed over the ground by the turn of the tide that was then flowing north. The tension in the tow was still exceeding 5,000 lb., and increased if the ship’s speed was increased. With the increase in sea with the increasing wind, the fluctuations in tension were increasing with time also. With still over one mile away from the overnight mooring the Nobska was able to easily tow the cage up to 2 knots speed and connected it to the temporary mooring west of the OOA site. After this operation the Nobska steamed back to the Port Authority Pier.